Remove utils::ensure_path_prefix

Was only used to validated paths passed as query parameters. Now that we match Genius URLs, it's no longer needed

src/utils.rs

@@ -17,11 +17,3 @@ pub fn path_from_url(url: &str) -> String {
     url.splitn(4, '/').last().unwrap().to_owned()
 }
 
-pub fn ensure_path_prefix(prefix: &'static str, path: &str) -> String {
-    let path = path.trim_start_matches('/');
-    if path.starts_with(prefix) {
-        path.to_string()
-    } else {
-        format!("{}/{}", prefix, path)
-    }
-}